SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/hamg-sunspots-hf

How does a higher sunspot number affect HF propagation?

Better odds of good propagation at higher frequencies.

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  1. More sunspots mean better odds on higher frequencies ✔
  2. A zero sunspot number means no propagation on any band
  3. Lower sunspot numbers mean better sporadic E

Why: More sunspots mean a more active Sun and a more strongly ionized upper atmosphere. That lets higher HF bands such as 15, 12 and 10 meters bend signals back to Earth.

Huh, didn't know that: The 20 meter band can usually support worldwide daytime propagation at any point in the solar cycle.

The dad joke
You know you're married to a ham when his sense of well-being is tied to the sunspot cycle.
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References

Answer: More sunspots mean better odds on higher frequencies. More sunspots mean a more active Sun and a more strongly ionized upper atmosphere. That lets higher HF bands such as 15, 12 and 10 meters bend signals back to Earth.

  1. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    Higher sunspot numbers generally indicate a greater probability of good propagation at higher frequencies
    Checked 2026-10-11.
  2. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    At any point
    Checked 2026-10-11.

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